Na+-independent L-arginine transport in rabbit renal brush border membrane vesicles.
Biochim Biophys Acta
; 685(1): 71-7, 1982 Feb 08.
Article
em En
| MEDLINE
| ID: mdl-7059593
ABSTRACT
Na+-independent L-arginine uptake was studied in rabbit renal brush border membrane vesicles. The finding that steady-state uptake of L-arginine decreased with increasing extravesicular osmolality and the demonstration of accelerative exchange diffusion after preincubation of vesicles with L-arginine, but not D-arginine, indicated that the uptake of L-arginine in brush border vesicles was reflective of carrier-mediated transport into an intravesicular space. Accelerative exchange diffusion of L-arginine was demonstrated in vesicles preincubated with L-lysine and L-ornithine, but not L-alanine or L-proline, suggesting the presence of a dibasic amino acid transporter in the renal brush border membrane. Partial saturation of initial rates of L-arginine transport was found with extravesicular [arginine] varied from 0.005 to 1.0 mM. L-Arginine uptake was inhibited by extravesicular dibasic amino acids unlike the Na+-independent uptake of L-alanine, L-glutamine, glycine or L-proline in the presence of extravesicular amino acids of similar structure. L-Arginine uptake was increased by the imposition of an H+ gradient (intravesicular pH less than extravesicular pH) and H+ gradient stimulated uptake was further increased by FCCP. These findings demonstrate membrane-potential-sensitive, Na+-independent transport of L-arginine in brush border membrane vesicles which differs from Na+-independent uptake of neutral and acidic amino acids. Na+-independent dibasic amino acid transport in membrane vesicles is likely reflective of Na+-independent transport of dibasic amino acids across the renal brush border membrane.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Arginina
/
Sódio
/
Membrana Celular
/
Rim
/
Microvilosidades
Limite:
Animals
Idioma:
En
Ano de publicação:
1982
Tipo de documento:
Article